Board to board connectors are used to interconnect circuitry on a plurality of daughter boards to a mother board or backplane. These boards may be mounted in a vertical or horizontal relationship depending upon the configuration of the mating connector members.
The demand for connectors that solve problems such as common mode noise and crosstalk has increased with the density and speed of electronic circuitry. It is desirable, therefore, to provide high density electrical connectors with means to provide a low inductance and low resistance ground connection from the connector to the circuit board to which it is attached.
U.S. Pat. No. 4,867,690 discloses an electrical connector system comprising a pin header having a plurality of rows of terminal members extending parallel to the sidewalls. The outermost rows of terminals adjacent the sidewalls are adapted to provide ground reference paths while the remaining rows of terminals are adapted to be mated to a receptacle member.
U.S. Pat. No. 4,655,518 discloses a two-piece connector assembly that provides grounding contacts along the dielectric sidewalls of the respective connectors. The terminal members of the pin header are positioned in recesses along the inside surfaces of the sidewall with the contact portion being a convex shape single resilient beam facing inwardly toward the pin terminals positioned between the sidewalls. In the receptacle member, ground contacts are placed along the outside surfaces of the sidewall so that they will slidably engage resilient beams in the pin header when the connectors are mated.
It is also desirable in certain applications to provide means for shorting together any two adjacent electrical contacts when a mating connector and board is removed from a system thereby providing a switching effect to maintain electrical continuity of the system. The "built in" switches eliminate the need for additional parts to provide the same capability.
For high density, high speed electronic systems it is generally desirable to provide means for shielding modules within the system for protection from EMI/RFI. It is desirable, therefore, that connector assemblies used within the system include means for facilitating interconnection of module shields to ground planes within the mother board or backplane. For purposes of this application, the terms "shielded pin header", "shielded receptacle" or "shielded connector assembly" are to be understood to mean members having a ground plate or other structure that provides the above described capability.
Furthermore, it is desirable that the mating members of grounded or shielded connector assembly also be matable with respective existing complementary nongrounded or shielded embers to provide a cost effective manner of upgrading existing electronic systems such as computers and instrumentation.